About this brief This paper summarises findings from a rigorous literature review entitled Early childhood development and cognitive development in developing countries (Rao et al. 2013)\*. It was led by the Comparative Education Research Centre at The University of Hong Kong, and funded by the Department for International Development’s (DFID) Research and Evidence Division.

The review assembled evidence to determine how, why and under what conditions Early Childhood Development (ECD) interventions are effective in promoting cognitive development of children living in low- and middle-income countries (LMICs). ECD interventions include (i) programmes for children under three years and their families; (ii) informal and formal services for children ranging from three to six years, which aim to prepare the child for formal primary education; and (iii) support for children in the early grades of primary school.

The studies were grouped by intervention: parent-focused, child-focused, nutrition and health interventions and income-supplementation programmes. The body of evidence also includes comprehensive programmes that provide a mix of different services (for example, parental support, preschool education and healthcare services).

How to use this brief This brief provides an overview of key evidence to assist policy-makers and researchers in assessing the research in this field. Policy-makers should, of course, carefully consider their own specific context.

Methodology Relevant keywords (early childhood development and cognitive development) were used to search for evidence in nine electronic databases, reference lists of journals, and specialist websites. Only studies published after 1992 were considered. Following a rigorous screening procedure, 111 studies conducted in 40 developing countries were selected for inclusion. These 111 studies were coded to specify their methodological rigour and consistency. Findings from 70 of these 111 studies were statistically combined using meta-analyses. In addition, narrative summaries of 14 were prepared to help identify key messages from different studies.

Research gaps There is limited evidence on both cost effectiveness and long-term effects of interventions. Only 38 of the 70 studies considered the effects of an intervention six months after completion. Further, studies did not reflect the population distributions of children in developing countries. Most of the studies were conducted in Latin America and the Caribbean (38%) and in South Asia (28%).

Key findings

- A large, high-quality evidence base shows ECD interventions focusing on (i) parental support; (ii) early stimulation and education; (iii) nutrition and health; (iv) income supplementation; and (v) comprehensive and integrated programmes have positive effects on children’s cognitive development.
- The largest effects are associated with comprehensive programmes.
- Parent-focused interventions are most effective when both the child and parent are involved.
- Using well-qualified early childhood educators and community health workers led to better cognitive outcomes for children across programmes. Summary map of evidence

The figure below is based on 70 studies (115 interventions) in 30 developing countries that reported the necessary information for effect-size calculation. One study could have more than one intervention group and intervention was used as the unit of analysis. Further detail on effect size by intervention is included in the main report. The height of the textboxes in the figure represents the range of effect sizes for each type of intervention.

Notes on context

1. **Nutrition and health** interventions were most common in Asia, although interventions were also identified in Africa and Latin America and the Caribbean.
2. **Child-focused educational** interventions were most common in Asia and Africa and the majority of them involved early education programmes for children over three years of age.
3. **Parent-focused interventions** were implemented in different parts of the world. Change agents were usually professional or paraprofessional community health workers who worked with parents and children together.
4. **Other comprehensive programmes** were implemented in Asia and Latin America. These programmes typically included parenting education, preschool education and nutrition interventions.
5. **Income supplementations** were found exclusively in Latin America and the Caribbean. The effects of both stand-alone and integrated cash-transfer programmes were evaluated and the findings from different interventions were consistent with one another. Outline of evidence

Parent-focused interventions

| Characteristics of effective interventions | Factors unrelated to intervention effectiveness | |--------------------------------------------|-----------------------------------------------| | ✓ Include guided practice for parents | • Parent-alone programmes | | ✓ Involve both parents and children | • Programmes for children above three years that last for less than two years | | ✓ Provide opportunities for sharing and group discussion | | | ✓ Include at least two contacts between parents and change agents | | | ✓ Have regular monitoring of implementation | | | ✓ Use culturally appropriate materials | |

Taken together, parent-focused interventions generally produced small positive effects on cognitive development. Interventions that included both parent and child and focused on parenting skills commonly had larger positive effects than did parent-only programmes or information-based interventions. Short-term interventions were effective for children under 18 months, but interventions that lasted at least two years had sustainable positive effects on older children. Almost all of the parenting interventions focused on teaching parents to promote child development through play, often utilising homemade toys or other readily available household items. All interventions had key messages or defined curricula. Parent-focused interventions led to beneficial changes in parents, positively influencing parent-child relationships and the general atmosphere of the home. These may have helped support continuous cognitive development beyond the intervention period.

Child-focused educational interventions

| Characteristics of effective interventions | Factors unrelated to intervention effectiveness | |--------------------------------------------|-----------------------------------------------| | ✓ High-quality programme with qualified and trained early childhood educators | • Mere participation in a programme (as quality of stimulation was important) | | ✓ Some degree of structure | • Location of the intervention | | ✓ Child-appropriate curriculum | • Age of the child |

Child-focused educational interventions produced generally consistent positive effects on children’s cognitive development. The majority of these interventions for children over three years were implemented in preschools or child-care centres. The duration of interventions ranged from one month to several years. There was a positive relationship between the quality of educational interventions and child outcomes. High-quality programmes had well-qualified and properly trained educators. They also had a moderate degree of structure and child-appropriate curricula and instruction.

Nutrition and health interventions

| Characteristics of effective interventions | Factors unrelated to intervention effectiveness | |--------------------------------------------|-----------------------------------------------| | ✓ The capacity to plan, manage, deliver and monitor interventions | • Type of supplement provided | | ✓ Prenatal and post-partum micro-nutrient (MM) supplement | • Duration of intervention | | ✓ MM-fortified food until two years (versus MM alone) | • Number of contacts | | ✓ MM-fortified biscuits and milk | • Location of intervention | | | • Guidance and training of change agents |

The results from 20 nutrition and health studies examined together showed that these interventions as a whole had smaller effects on cognitive development than other interventions. However, it is important to emphasise that children not only benefited directly from the health effects of nutritional supplements, but also showed significant cognitive gains within the short assessment periods. The level of effect sizes did not vary based on the type of supplementary nutrition components provided. In general, the frequency, duration and location of interventions, as well as the characteristics and training of change agents (usually community health workers) were not clearly related to the effect size. The factors determining programme success were often dependent on capacity to plan, manage, deliver and monitor these services. Our findings of the small effect of nutrition on cognitive development may be due to the use of less sensitive tools for measuring cognitive development and because the interrelationships between socioeconomic circumstances, nutrition and cognitive development make it difficult to isolate the specific effects of malnutrition on cognitive development.

**Income supplementation**

| Characteristics of effective interventions | Factors unrelated to intervention effectiveness | |-------------------------------------------|-----------------------------------------------| | ✓ Target the most disadvantaged | • Parent-alone programmes | | ✓ Earlier enrolment | • Short duration for children above three years| | ✓ Longer duration | |

Income-supplementation programmes had small-to-medium-sized positive effects on cognitive development. In the interventions studied, the family (usually the mother) only received the benefits for compliance with certain requirements. The exact reason why income-supplementation programmes, particularly conditional cash-transfer programmes (CTPs), work is hard to pinpoint because the conditions they are associated with are often themselves interventions (medical checks, parental counselling or programme attendance). However, available studies do seem to suggest that earlier enrolment and longer duration of exposure produce larger positive effects in young children.

**Other comprehensive programmes**

Evaluations of large-scale comprehensive programmes indicate that children in LMICs benefit from comprehensive early-intervention programmes that typically integrate parenting support, nutrition and healthcare services and education. The programmes reviewed demonstrated some overarching similarities: (i) they all targeted children and parents in low-income families, (ii) they aimed to benefit large numbers of children, (iii) they included a mix of different services and children from a range of ages, and (iv) most of the interventions fostered community involvement, encouraging the beneficiaries of the programme to become agents of change themselves. The diagram below shows how parent-focused, child-focused educational, and nutrition and health interventions can enhance cognitive development, and is suggested by the synthesis of quantitative findings from large-scale interventions that evaluated comprehensive programmes.

This material has been funded by the Department for International Development. However, the views expressed do not necessarily reflect the department’s official policies. References

Rao, N, Sun, J, Wong, JMS, Weekes, BS, Ip, P, Shaeffer, S, Young, ME, Bray, M, Chen, E, Lee, D (2013) Early childhood development and cognitive development in developing countries: A rigorous literature review (pp. 101). DFID, UK Government

List of 70 studies included in the meta-analyses. The rigorous literature review included 111 studies.

Parent-focused interventions

01. Aboud, FE (2007) Evaluation of an early childhood parenting program in rural Bangladesh. Journal of Health, Population and Nutrition 25(1): 3–13.
02. Aboud, FE, Akhter, S (2011) A cluster-randomized evaluation of a responsive stimulation and feeding intervention in Bangladesh. Pediatrics, 127(5): e1191–e1197.
03. Aboud, FE, Singla, DR, Nahil, MI, Borisova, I (2012) Parenting program for birth – 3 years old children in rural Bangladesh to address early childhood health, growth and development. Unpublished manuscript.
04. Eickmann, SH, Lima, ACV, Guerra, MQ, Lima, MC, Lira, PIC, Huttly, SRA, Ashworth, A (2003) Improved cognitive and motor development in a community-based intervention of psychosocial stimulation in northeast Brazil. Developmental Medicine & Child Neurology 45(8): 536–541.
05. Gardner, JM, Powell, CA, Baker-Henningham, H, Walker, SP, Cole, TJ, Grantham-McGregor, SM (2005) Zinc supplementation and psychosocial stimulation: Effects on the development of undernourished Jamaican children. The American Journal of Clinical Nutrition 82(2): 399–405.
06. Gardner, JM, Walker, SP, Powell, CA, Grantham-McGregor, S (2003) A randomized controlled trial of a home-visiting intervention on cognition and behavior in term low birth weight infants. The Journal of Pediatrics 143(5): 634–639.
07. Grantham-McGregor, SM, Walker, SP, Chang, SM, & Powell, CA (1997) Effects of early childhood supplementation with and without stimulation on later development in stunted Jamaican children. The American Journal of Clinical Nutrition 66(2): 247–253.
08. Hamadani, JD, Huda, SN, Khatun, F, Grantham-McGregor, SM (2006) Psychosocial stimulation improves the development of undernourished children in rural Bangladesh. The Journal of Nutrition 136(10): 2,645–2,652.
09. Jin, X, Sun, Y, Jiang, F, Ma, J, Morgan, C, Shen, X (2007) “Care for Development” intervention in rural China: A prospective follow-up study. Journal of Developmental & Behavioral Pediatrics 28(3): 213–218.
10. Kotamani, H (2008) Impacts of dialogical storybook reading on young children’s reading attitudes and vocabulary development. Reading Improvement 45(2): 55–61.
11. Nahar, B, Hamadani, JD, Ahmed, T, Tofail, F, Rahman, A, Huda, SN, Grantham-McGregor, SM (2009) Effects of psychosocial stimulation on growth and development of severely malnourished children in a nutrition unit in Bangladesh. European Journal of Clinical Nutrition 63: 725–730.
12. Powell, C, Baker-Henningham, H, Walker, S, Gernay, J, Grantham-McGregor, S (2004) Feasibility of integrating early stimulation into primary care for undernourished children: Cluster randomised controlled trial. British Medical Journal 329(7457), 89.
13. Vazir, S, Engle, P, Balakrishna, N, Griffiths, PL, Johnson, SL, Creed-Kanashiro, H, Fernandez Rao S, Bentley, ME (2013) Cluster-randomized trial on complementary and responsive feeding education to caregivers found improved dietary intake, growth and development among rural Indian toddlers. Maternal & Child Nutrition 9(1): 99–117.
14. Walker, SP, Chang, SM, Powell, CA, Grantham-McGregor, SM (2005) Effects of early childhood psychosocial stimulation and nutritional supplementation on cognition and education in growth-retarded Jamaican children: Prospective cohort study. The Lancet 365(9499): 1,804–1,807.
15. Walker, SP, Chang, SM, Powell, CA, Grantham-McGregor, SM (2004) Psychosocial intervention improves the development of term low-birth-weight infants. The Journal of Nutrition 134(6): 1,417–1,423.
16. Walker, SP, Chang, SM, Younger, N, Grantham-McGregor, SM (2010) The effect of psychosocial stimulation on cognition and behavior at 6 years in a cohort of term low-birthweight Jamaican children. Developmental Medicine & Child Neurology 52(7): e148–e154.
17. Walker, SP, Grantham-McGregor, SM, Powell, CA, Chang, SM (2000) Effects of growth restriction in early childhood on growth, IQ, and cognition at age 11 to 12 years and the benefits of nutritional supplementation and psychosocial stimulation. The Journal of Pediatrics 137(1): 36–41.
18. Watanabe, K, Flores, R, Fujiwara, J, Tran, LTH (2005) Early childhood development interventions and cognitive development of young children in rural Vietnam. The Journal of Nutrition 135(6): 1,918–1,925.

Child-focused educational interventions

19. Aboud, FE (2006) Evaluation of an early childhood preschool program in rural Bangladesh. Early Childhood Research Quarterly 21(1): 46–60.

20. Aboud, FE, Hossain, K (2011) The impact of primary school on primary school achievement in Bangladesh. Early Childhood Research Quarterly 26(2): 237–246.

21. Aboud, FE, Hossain, K, O’Gara, C (2008) The Succeed Project: Challenging early school failure in Bangladesh. Research in Comparative and International Education 3(3): 295–307.

22. American Institutes for Research (2012) Getting Ready for School: A child-to-child approach, programme evaluation for year one grade one outcomes. New York: UNICEF.

23. Berument, SK, Sönmez, D, Eyüpoğlu, H (2011) Supporting language and cognitive development of infants and young children living in children’s homes in Turkey. Child care, health and development 38(5): 743–752.

24. Education Development Center, Inc. (EDC) (2009) Radio Instruction to Strengthen Education (RISE) in Zanzibar. Boston: EDC.

25. Leroy, JL, Gertler, P, Martinez, S (2012) The impact of day care on maternal labor supply and child development in Mexico: Final data analysis report. Mexico: Instituto Nacional de Salud Pública.

26. Maimberg, L-E, Mwaura, P, Sylva, K (2011) Effects of a preschool intervention on cognitive development among East-African preschool children: A flexible time-coded growth model. Early Childhood Research Quarterly 26(1): 124–133.

27. Martinez, S, Naudeau, S, Pereira, V (2012) The promise of preschool in Africa: A randomized impact evaluation of ECD in rural Mozambique. New Delhi, India: International Initiative for Impact Evaluation (3ie).

28. Moore, AC, Akhter, S, Aboud, FE (2008) Evaluating an improved quality preschool program in rural Bangladesh. International Journal of Educational Development 28(2): 118–131.

29. Mwaura, PAM, Sylva, K, Maimberg, L-E (2008) Evaluating the Madrasa preschool programme in East Africa: A quasi-experimental study. International Journal of Early Years Education 16(3): 237–255.

30. Nair, MKC, Philip, E, Jeyaseelan, L, George, B, Mathews, S, Padma, K (2009) Effect of Child Development Centre model early stimulation among at-risk babies: A randomized controlled trial. Indian Pediatrics 46(Supplement): S20–S26.

31. Nonoyama-Tarumi, Y, Breidenberg, K (2009) Impact of school readiness program interventions on children’s learning in Cambodia. International Journal of Educational Development 29(1): 39–45.

32. Opel, A, Ameer, SS, Aboud, FE (2009) The effect of preschool dialogic reading on vocabulary among rural Bangladeshi children. International Journal of Educational Research 48(1): 12–20.

33. Piramal, R, Law, J (2010) Evaluating a programme to enhance vocabulary development in pre-schoolers. International Journal of Language & Communication Disorders 36(s1): 222–227. Nutrition and health interventions

34. Castillo-Durán, C, Perales, CG, Hertrampf, ED, Marin, VB, Rivera, FA, Icaza, G (2001) Effect of zinc supplementation on development and growth of Chilean infants. The Journal of Pediatrics 138(2): 229–235.

35. Caulfield, LE, Putnick, DL, Zavaleta, N, Lazarte, F, Albornoz, C, Chen, P, Dipietro JA, Bornstein, MH (2010) Maternal gestational zinc supplementation does not influence multiple aspects of child development at 54 mo of age in Peru. The American Journal of Clinical Nutrition 92(1): 130–136.

36. Chen, C-M, Wang, Y-Y, Chang, S-Y (2010) Effect of in-home fortification of complementary feeding on intellectual development of Chinese children. Biomedical and Environmental Sciences 23(2): 83–91.

37. Christian, P, Morgan, ME, Murray-Kolb, L, LeClerq, SC, Khatri, SK, Schaefler, B, Cole PM, Katz J, Tielsch, JM (2011) Preschool iron-folic acid and zinc supplementation in children exposed to iron-folic acid in utero confers no added cognitive benefit in early school-age. The Journal of Nutrition 141(11): 2,042–2,048.

38. Christian, P, Murray-Kolb, L, Khatri, SK, Katz, J, Schaefler, BA, Cole, PM, LeClerq SC, Tielsch, JM (2010) Prenatal micronutrient supplementation effects on intellectual and motor function in school-aged children. The Journal of the American Medical Association 304(24): 2,716–2,723.

39. Hamadani, JD, Fuchs, GJ, Osendarp, SJM, Huda, SN, Grantham-McGregor, SM (2002) Zinc supplementation during pregnancy and effects on mental development and behaviour of infants: A follow-up study. The Lancet 360: 290–294.

40. Hamadani, JD, Fuchs, GJ, Osendarp, SJM, Khatun, F, Huda, SN, Grantham-McGregor, SM (2001) Randomized controlled trial of the effect of zinc supplementation on the mental development of Bangladeshi infants. The American Journal of Clinical Nutrition 74(3): 381–386.

41. Idrisradina, P, Pollitt, E (1993) Reversal of developmental delays in iron-deficient anemic infants treated with iron. The Lancet 341: 1–4.

42. Li, Q, Yan, H, Zeng, L, Cheng, Y, Liang, W, Dang, S, Wang Q, Tsuji, I. (2009) Effects of maternal multimicronutrient supplementation on the mental development of infants in rural Western China: Follow-up evaluation of a double-blind, randomized, controlled trial. Pediatrics 123: e685–e690.

43. Lind, T, Lønnerdal, B, Stenlund, H, Gamayanti, IL, Ismail, D, Seswadhanra, R, Persson, L-A (2004) A community-based randomized controlled trial of iron and zinc supplementation in Indonesian infants: Effects on growth and development. The American Journal of Clinical Nutrition 80(3): 729–736.

44. Lozoff, B, De Andrade, I, Castillo, M, Smith, JB, Walter, T, Pino, P (2003) Behavioral and developmental effects of preventing iron-deficiency anemia in healthy full-term infants. Pediatrics 111(4): 846–854.

45. Maluccio, JA, Hoddinott, J, Behrman, JR, Martorell, R, Quisumbing, AR, Stein, AD (2009) The impact of improving nutrition during early childhood on education among Guatemalan children. The Economic Journal 119(537): 734–763.

46. Murray-Kolb, LE, Khatri, SK, Katz, J, Schaefler, BA, Cole, PM, LeClerq, SC, Morgan ME, Tielsch JM, Christian, P (2012) Preschool micronutrient supplementation effects on intellectual and motor function in school-aged Nepalese children. Archives of Pediatrics & Adolescent Medicine 166(5): 404–410.

47. Nga, TT, Winichagoon, P, Dijkhuizen, MA, Khan, NC, Wasantwisut, E, Wieringa, FT (2011) Decreased parasite load and improved cognitive outcomes caused by deworming and consumption of multi-micronutrient fortified biscuits in rural Vietnamese schoolchildren. The American Journal of Tropical Medicine and Hygiene 85(2): 333–340.

48. Pollitt, E, Gorman, KS, Engle, PL, Martorell, R, Rivera, J, Wachs, TD, Scrimshaw, NS (1993) Early supplementary feeding and cognition: Effects over two decades. Monographs of the Society for Research in Child Development 58(7, Serial No. 253): 1–118.

49. Pongcharoen, T, Díaz-Gómez, AM, Ramakrishnan, U, Winichagoon, P, Flores, R, Martorell, R (2011) Long-term effects of iron and zinc supplementation during infancy on cognitive function at 9 y of age in northeast Thai children: A follow-up study. The American Journal of Clinical Nutrition 93(3): 636–643.

50. Prado, EL, Alcock, KJ, Muadz, H, Ullman, MT, Shankar, AH (2012) Maternal multiple micronutrient supplements and child cognition: A randomized trial in Indonesia. Pediatrics 130(3): e536–e546.

51. Schmidt, MK, Musilmatun, S, West, CE, Schullink, W, Hauvast, JGAU (2004) Mental and psychomotor development in Indonesian infants of mothers supplemented with vitamin A in addition to iron during pregnancy. British Journal of Nutrition 91: 279–285.

52. Taneja, S, Bhandari, N, Bahl, R, Bhan, MK (2005) Effect of zinc supplementation on mental performance of children aged 12 to 18 months: A randomized, double-blind trial. The Journal of Pediatrics 146(4): 506–511.

53. Tofail, F, Persson, LA, El Arifeen, S, Hamadani, JD, Mehrin, F, Ridout, D, Ekström EC, Huda SN, Grantham-McGregor, SM (2008) Effects of prenatal food and micronutrient supplementation on infant development: A randomized trial from the Maternal and Infant Nutrition Interventions, Matlab (MINIMat) study. The American Journal of Clinical Nutrition 87(3): 704–711.

54. van der Merwe, LF, Moore, SE, Fullford, AJ, Halliday, KE, Drameh, S, Young, S, Prentice, AM (2013) Long-chain PUFA supplementation in rural African infants: A randomized controlled trial of effects on gut integrity, growth, and cognitive development. American Journal of Clinical Nutrition 97(1): 45–57.

Income supplementation

61. Behrman, JR, Cheng, Y, Todd, PE (2004) Evaluating preschool programs when length of exposure to the program varies: A nonparametric approach. The Review of Economics and Statistics 86(1): 108–132.

62. Fernández, LCH, Hidrobo, M (2011) Effect of Ecuador's cash transfer program (Bono de Desarrollo Humano) on child development in infants and toddlers: A randomized effectiveness trial. Social Science & Medicine 72(9): 1,437–1,446.

63. Fernández, LCH, Gertler, PJ, Neufeld, LM (2008) Role of cash in conditional cash transfer programmes for child health, growth, and development: An analysis of Mexico's Oportunidades. The Lancet 371: 828–837.

64. Fernández, LCH, Gertler, PJ, Neufeld, LM (2009) 10-year effect of Oportunidades, Mexico's conditional cash transfer programme, on child growth, cognition, language, and behaviour: A longitudinal follow-up study. The Lancet 374: 1997–2005.

65. Gertler, PJ, Fernald, LC (2004) The medium term impact of Oportunidades on child development in rural areas. Unpublished manuscript.

66. Paxson, C, Schady, N (2010) Does money matter? The effects of cash transfers on child development in rural Ecuador. Economic Development and Cultural Change 59(1): 187–229. Other comprehensive programmes

67. Ade, A, Gupta, SS, Maliye, C, Deshmukh, PR, Garg, BS (2010) Effect of improvement of pre-school education through Anganwadi center on intelligence and development quotient of children. Indian Journal of Pediatrics 77(5): 541–546.

68. Armecin, G, Behrman, JR, Duazo, P, Ghuman, S, Gultiano, S, King, EM, Lee, N (2006) Early childhood development through an integrated program: Evidence from the Philippines (Policy Research Working Paper 3922). Washington, DC: World Bank.

69. Pearson, S, Austin, AMB, de Aquino, CN, de Burró, EU (2008) Cognitive development and home environment of rural Paraguayan infants and toddlers participating in Pastoral del Niño, an early child development program. Journal of Research in Childhood Education 22(4): 343–362.

70. Rao, N (2010) Preschool quality and the development of children from economically disadvantaged families in India. Early Education and Development 21(2): 167–185.

This brief was prepared by Nirmala Rao, Jessie Wong and Jin Sun on the basis of the rigorous literature review co-authored with Brendan Weekes, Patrick Ip, Sheldon Shaeffer, Mary Young, Mark Bray, Eva Chen and Diana Lee.